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- Title
In Situ Observation of the Zr Poisoning Effect in Al Alloys Inoculated by Al-Ti-B.
- Authors
Jia, Yiwang; Wang, Shubin; Huang, Haijun; Wang, Donghong; Fu, Yanan; Zhu, Guoliang; Dong, Anping; Du, Dafan; Shu, Da; Sun, Baode
- Abstract
In situ synchrotron X-ray radiography observations of the Zr-poisoning phenomenon of an Al-20 wt pct Zn alloy inoculated by Al-5Ti-1B were carried out. The effects of Zr addition on heterogeneous nucleation, grain growth, and final grain size were quantitatively studied and further analyzed using the interdependence model. The experimental results show that the undercooling needed for nucleation increases and the nucleation rate decreases at the early stage of solidification with Zr addition, resulting in fast grain growth, a high solidification rate and increased severity of solute segregation in the solid-liquid coexistence regions. At the same time, the poisoning is a progressive process that is enhanced with the increasing Zr content, holding temperature, and holding time. The nucleation-free zone of the Zr-containing sample, either measured from the radiographs or calculated by the interdependency theory, is larger than that of the Zr-free sample. Our analysis shows that both the increase in the nucleation-free zone and the average interparticle spacing of the most potent available nucleation particles contribute to the increase of the grain size caused by Zr poisoning.
- Subjects
ALLOY analysis; METALLOGRAPHY of alloys; GRAIN growth; METAL crystal growth; SOLIDIFICATION
- Publication
Metallurgical & Materials Transactions. Part A, 2018, Vol 49, Issue 10, p4771
- ISSN
1073-5623
- Publication type
Article
- DOI
10.1007/s11661-018-4834-6